Analysis of Carbohydrate–Carbohydrate Interactions Using Sugar-Functionalized Silicon Nanoparticles for Cell Imaging

Protein-carbohydrate binding depends on multivalent ligand display that is even more important for low affinity carbohydrate–carbohydrate interactions. Detection and analysis of these low affinity multivalent binding events are technically challenging. We describe the synthesis of dual-fluorescent sugar-capped silicon nanoparticles that proved to be an attractive tool for the analysis of low affinity interactions. These ultrasmall NPs with sizes of around 4 nm can be used for NMR quantification of coupled sugars. The silicon nanoparticles are employed to measure the interaction between the cancer-associated glycosphingolipids GM3 and Gg3 and the associated kD value by surface plasmon resonance experiments. Cell binding studies, to investigate the biological relevance of these carbohydrate–carbohydrate interactions, also benefit from these fluorescent sugar-capped nanoparticles.